gunboats
The book "Divided Waters" by Ivan Musicant is a good source of information about both navies. A couple of pretty good chapters about the background of the Monitor and the Virginia (Merrimack) , the battle and the aftermath. I usually hit the bibliographies of books and find out who the author used as sources. I would also recommend "By Sea and By River" by Bern Anderson. Hope this helps
Calicoboy